[mythtv-users] Okay, slow down, HDTV idiot here...
Michael T. Dean
mtdean at thirdcontact.com
Sat Jul 17 01:50:17 EDT 2004
Dean Blackburn wrote:
> Excuse me for asking the most blatantly dumb question out there, but
> even with all the discussions about broadcast flag and HDTV, there are
> no cards out there, at all*, that can do anything other than record
> broadcast (not cable) HDTV signals, yes?
Correct. The pcHDTV card, which AFAIK is the only existing card with
Linux driver support, is only usable for ATSC OTA (Over-The-Air) channels.
> Are there even any plans for cards that can receive cable HDTV signals?
Cable ATSC HDTV is modulated using Quadrature Amplitude Modulation
(QAM), but OTA ATSC is modulated using Vestigial Side-Band (VSB)
modulation (generally 8VSB). DVICO is working on QAM support for the
Fusion HDTV3 ( http://www.dvico.com/products_mul_hd3.html ), the card
for which they have offered to provide technical specifications to allow
open-source developers to write a Linux driver.
Even if DVICO gets QAM working reliably with cable signals from multiple
providers (currently, they seem to have pretty good support for 256QAM,
but 64QAM support has a way to go, and I have no idea about 16QAM,
32QAM, and 128QAM), it will only be usable for _unencrypted_ cable
channels. Since most cable HTDV channels are (or will be) encrypted by
the cable provider (generally, cable companies will only provide the
local ATSC OTA channels unencrypted), even the Fusion HDTV3 with QAM
support would be unable to receive most channels: it would most likely
be limited to the same channels available with an ATSC OTA card.
Although it's theoretically possibly to circumvent the encryption, doing
so would be in violation of US copyright law (DMCA).
> Perhaps I missed the announcement or something, but I just can't find
> anything like this...
Nope, you didn't miss the announcement. The networks, content
providers, and service providers are doing their best to make sure that
the American public doesn't realize how much of the fair-use provisions
to which we've grown accustomed are being taken away with the switch to
HDTV--whether from the encrypted content transmitted by our providers or
from the broadcast flag.
But, don't worry. Your cable or satellite company will surely offer you
some specialized (=proprietary) equipment that provides 1/10 the
capabilities of Myth for only a "small" monthly fee... ;)
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